title: Binding of transition metal ions to albumin: sites, affinities and rates.
abstract: BACKGROUND
  Serum albumin is the most abundant protein in the blood and cerebrospinal fluid and plays a fundamental role in the distribution of essential transition metal ions in the human body. Human serum albumin (HSA) is an important physiological transporter of the essential metal ions Cu(2+), and Zn(2+) in the bloodstream. Its binding of metals like Ni(2+), Co(2+), or Cd(2+) can occur in vivo, but is only of toxicological relevance. Moreover, HSA is one of the main targets and hence most studied binding protein for metallodrugs based on complexes with Au, Pt and V.
  
  
  METHODS
  We discuss i) the four metal-binding sites so far described on HSA, their localization and metal preference, ii) the binding of the metal ions mentioned above, i.e. their stability constants and association/dissociation rates, their coordination chemistry and their selectivity versus the four binding sites iii) the methodology applied to study issues of items i and ii and iv) oligopeptide models of the N-terminal binding site.
  
  
  CONCLUSIONS
  Albumin has four partially selective metal binding sites with well-defined metal preferences. It is an important regulator of the blood transport of physiological Cu(II) and Zn(II) and toxic Ni(II) and Cd(II). It is also an important target for metal-based drugs containing Pt(II), V(IV)O, and Au(I).
  
  
  CONCLUSIONS
  The thorough understanding of metal binding properties of serum albumin, including the competition of various metal ions for specific binding sites is important for biomedical issues, such as new disease markers and design of metal-based drugs. This article is part of a Special Issue entitled Serum Albumin.
authors.affiliation: Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5A, Warsaw 02-106, Poland. Electronic address: wbal@ibb.waw.pl.
authors.forename: Wojciech
authors.initials: W
authors.lastname: Bal
authors.forename: Magdalena
authors.initials: M
authors.lastname: Sokołowska
authors.forename: Ewa
authors.initials: E
authors.lastname: Kurowska
authors.forename: Peter
authors.initials: P
authors.lastname: Faller
mesh_terms: D001665:Binding Sites; D007700:Kinetics; D008670:Metals / Q000737:chemistry / Q000378:metabolism*; D008958:Models, Molecular; D015394:Molecular Structure; D011485:Protein Binding; D012709:Serum Albumin / Q000737:chemistry / Q000378:metabolism*
chemical_list: D008670:Metals; D012709:Serum Albumin
keywords: Albumin; Binding constants; Metal ions